Conventionally known as this kind of technique is a laser processing method which irradiates a substrate formed with a multilayer part including a plurality of functional devices while locating a converging point therewithin, so as to form a modified region within the substrate along a line to cut, and cuts the substrate and multilayer part from the modified region acting as a start point (see, for example, Patent Document 1).    Patent Document 1: Japanese Patent Application Laid-Open No. 2003-334812